Electronic devices which are operated by touching an image such as an icon displayed on a screen are becoming widespread. Display devices which are used in such electronic devices are also called touch panels (or touch screens). An electrostatic capacitance type touch sensor is employed in a touch panel. An element which detects a change in electrostatic capacitance between a pair of sensor electrodes called a Tx electrode and Rx electrode as an input signal is included in an electrostatic capacitance type touch sensor.
A conventional touch panel includes a structure in which a touch sensor panel and display panel overlap each other. However, a structure in which two panels overlap each other increases the thickness of a display device which is a problem. For example, in a display device which curves or bends known as a flexible display, a structure in which a touch sensor panel and display panel overlap each other is the cause of obstruction to flexibility.
Therefore, a structure in which the function of a touch sensor is incorporated within a display panel is disclosed. For example, an in-cell type display device is disclosed in which a first detection electrode and a second detection electrode are arranged sandwiching an inorganic insulation film arranged as a sealing film in a display panel which uses an organic electroluminescence element (called an “organic EL element” herein), and a touch sensor is arranged within the panel (for example, refer to Japanese Laid Open Patent Publication No: 2015-050245).
When attempting to install a touch sensor in a display panel, wiring for a connection with detection electrodes is required which increases the number of wiring layers. Since it is necessary to protect a display element using a sealing layer in a display panel, it is necessary to arrange a connection structure without degrading the sealing capability of a sealing layer when connecting wiring with a detection electrode or when connecting wiring connected to a detection electrode with a terminal electrode.